1. Field of the Invention
The invention relates to a diverter valve that selectively diverts water from a conventional kitchen faucet to one of two or more outlets, and more particularly, to a diverter valve having ceramic disk elements.
2. Description of the Related Art
Fluid valves using ceramic valve stacks comprising a fixed ceramic disk and a rotating ceramic disk, both of which have pass-through openings to control the flow of fluid through the valve by selective movement of the rotatable ceramic disk, are well known. They typically appear in various configurations, such as in-line valves, conventional faucets, diverter valves, and hydrants, to name a few. Almost all ceramic valves comprise a “stack-up” that traditionally includes a seal, a fixed ceramic disk, a rotating ceramic disk, and a bearing in contact with the rotating ceramic disk. The stack-up is typically contained within a valve body, which defines the various inlets and outlets to the fluid sources.
For such a valve to work properly, the fixed and rotating ceramic disks must be held together in compression with force (the stack-up pressure) sufficient to prevent fluid from leaking between the interface of the disks. At the same time, the torque required to rotate the rotatable ceramic disk must be within a predetermined value, so that a user can easily use the device. The torque is the force that a user must supply to the handle of the valve (or to the valve itself) to rotate the rotating disk with respect to the fixed disk to turn the valve through its various operating positions. Although there is some subjectivity in the predetermined torque value, the force must always remain low enough to permit the weakest of users to easily operate the valve.
Commonly assigned U.S. Pat. No. RE35,545 discloses mounting a retainer to a positive stop in order to obtain a repeatable stack up pressure. Commonly assigned U.S. Pat. Nos. 6,405,756 and 6,575,196 disclose a means of reducing the stack up pressure. Normally, balancing the stack up pressure and torque is not a problem with these solutions, but in a valve with complex flows through the disks, e.g. a diverter valve, it has been found that uneven hydraulic pressures on the disks tend to cause leaks. Moreover, risk of leaks and higher costs attend existing diverter valves where flow must be directed from the rotatable ceramic through a lower housing.
Thus, there is a need for a ceramic diverter valve that balances hydraulic pressures within the ceramic disks, maintains a sufficiently low operating torque, and more reliably directs flow through the rotatable disk to the outlets.